Data directed analysis or acquisitions (“DDA”) has long been established as a useful tool for the analysis of complex mixtures due to the added specificity of the mass filtering step. More recently, ion mobility spectrometry (“IMS”) based separations, when combined with mass separations with and without fragmentation, has also shown benefits for the analysis of such complex mixtures. This is due to the increased peak capacity resulting from, for example, the partial orthogonality of ion mobility and mass to charge ratio.
It has been shown how the combination of IMS with a quadrupole mass filter, a fragmentation device and a Time of Flight (“ToF”) mass analyser can improve the specificity, selectivity and duty cycle of tandem mass spectrometry experiments.
Reference is made to WO 2013/40132 (Micromass) and GB-2505265 (Micromass) which disclose multi-dimensional survey scans for improved data dependent acquisitions.
GB-2514455 (Micromass) discloses data dependent control of the intensity of ions separated in multiple dimensions.
GB-2513973 discloses a DDA experiment with reduced data processing.
WO 2008/025014 (Schwartz) discloses data-dependent selection of dissociation type in a mass spectrometer.
It is desired to provide an improved method of analysing ions.